
    <!DOCTYPE html>
    <html lang="zh-CN">
    <head>
      <meta charset="UTF-8">
      <meta name="viewport" content="width=device-width, initial-scale=1.0">
      <title>项目中sleep(0)是什么意思 - 交互式测验</title>
      <style>
        @import url('https://fonts.googleapis.com/css2?family=Noto+Sans+SC:wght@400;500;700&display=swap');
        
        body {
          font-family: 'Noto Sans SC', sans-serif;
          background-color: #f4f7f9;
          color: #333;
          display: flex;
          justify-content: center;
          align-items: center;
          min-height: 100vh;
          margin: 0;
          padding: 20px;
          box-sizing: border-box;
        }
        
        .main-wrapper {
            position: relative;
            width: 100%;
            max-width: 900px; /* Wider to accommodate buttons */
            display: flex;
            justify-content: center;
            align-items: center;
        }

        .quiz-container {
          background-color: #ffffff;
          border-radius: 16px;
          box-shadow: 0 8px 32px rgba(0, 0, 0, 0.1);
          width: 100%;
          max-width: 700px;
          overflow: hidden;
          z-index: 10;
        }

        .quiz-header {
          background-color: #4a90e2;
          color: white;
          padding: 20px 30px;
          text-align: center;
        }

        .quiz-header h1 {
          margin: 0;
          font-size: 24px;
          font-weight: 700;
        }
        
        .quiz-header p {
            margin: 5px 0 0;
            font-size: 14px;
            opacity: 0.9;
        }

        .quiz-body {
          padding: 30px;
        }

        .progress-bar {
            display: none; /* 隐藏进度条 */
            width: 100%;
            background-color: #e0e0e0;
            border-radius: 5px;
            height: 10px;
            margin-bottom: 20px;
        }

        #progress-indicator {
            height: 100%;
            width: 0%;
            background-color: #4caf50;
            border-radius: 5px;
            transition: width 0.3s ease;
        }

        #question-container {
          margin-bottom: 20px;
        }

        #question-text {
          font-size: 18px;
          font-weight: 500;
          line-height: 1.6;
          margin-bottom: 25px;
        }

        .options-list {
          list-style: none;
          padding: 0;
          margin: 0;
        }

        .option-item {
          background-color: #f8f9fa;
          border: 1px solid #dee2e6;
          border-radius: 8px;
          padding: 15px;
          margin-bottom: 12px;
          cursor: pointer;
          transition: background-color 0.2s ease, border-color 0.2s ease;
        }

        .option-item:hover {
          background-color: #e9ecef;
        }
        
        .option-item.selected {
            background-color: #d1e7fd;
            border-color: #4a90e2;
        }

        .quiz-footer {
          padding: 20px 30px;
          display: flex;
          justify-content: space-between; /* 将按钮分布在两侧 */
          align-items: center;
          min-height: 65px; /* Reserve space */
        }

        .nav-btn {
          background-color: #4a90e2;
          color: white;
          border: none;
          border-radius: 8px;
          padding: 10px 20px;
          font-size: 16px;
          font-weight: 500;
          cursor: pointer;
          transition: background-color 0.2s ease, transform 0.2s ease;
          box-shadow: 0 4px 12px rgba(0,0,0,0.15);
        }
        
        #next-btn {
            background-color: #28a745;
        }

        .nav-btn:hover {
          background-color: #357abd;
          transform: scale(1.05);
        }
        
        .nav-btn:disabled {
            background-color: #a0c3e8;
            cursor: not-allowed;
            opacity: 0.7;
        }

        #result-container {
            border-top: 1px solid #eee;
        }
        
        .result-box {
            border-radius: 8px;
            padding: 20px;
            margin-top: 20px;
        }
        
        .result-box.correct {
            background-color: #d4edda;
            border: 1px solid #c3e6cb;
            color: #155724;
        }

        .result-box.incorrect {
            background-color: #f8d7da;
            border: 1px solid #f5c6cb;
            color: #721c24;
        }
        
        .result-box h3 {
            margin-top: 0;
        }

        .explanation-text {
            margin-top: 15px;
            line-height: 1.7;
        }
        
        .source-text {
            font-style: italic;
            font-size: 14px;
            margin-top: 15px;
            color: #555;
        }

        
        .final-score-container {
            padding: 40px;
            text-align: center;
        }
        .final-score-container h2 {
            margin-top: 0;
            margin-bottom: 30px;
        }
        .score-summary {
            display: flex;
            justify-content: center;
            gap: 20px;
            margin-bottom: 40px;
            flex-wrap: wrap;
        }
        .score-card {
            background-color: #f8f9fa;
            border-radius: 12px;
            padding: 20px;
            width: 180px;
            box-shadow: 0 4px 12px rgba(0,0,0,0.05);
            border: 1px solid #e9ecef;
        }
        .score-card h3 {
            margin: 0 0 10px;
            font-size: 16px;
            font-weight: 500;
            color: #555;
        }
        .score-card p {
            margin: 0;
            font-size: 28px;
            font-weight: 700;
            color: #333;
        }
        .score-details table {
            width: 100%;
            font-size: 16px;
        }
        .score-details td {
            padding: 4px 0;
        }
        .score-details td:last-child {
            text-align: right;
            font-weight: 700;
        }
        .report-actions button {
            background-color: #fff;
            border: 1px solid #ccc;
            border-radius: 8px;
            padding: 12px 25px;
            font-size: 16px;
            cursor: pointer;
            margin: 0 10px;
            transition: background-color 0.2s ease, border-color 0.2s ease, transform 0.2s ease;
        }
        .report-actions button:hover {
            background-color: #f1f1f1;
            border-color: #bbb;
            transform: translateY(-2px);
        }
        .report-actions button.primary {
            background-color: #28a745;
            color: white;
            border-color: #28a745;
        }
        .report-actions button.primary:hover {
            background-color: #218838;
        }
        
        .hint-container {
            background-color: #e0f7fa;
            border: 1px solid #b2ebf2;
            border-radius: 8px;
            padding: 15px;
            margin-top: 20px;
            color: #006064;
            font-size: 15px;
            line-height: 1.6;
            display: none; /* 默认隐藏 */
        }
      </style>
    </head>
    <body>
      <div class="main-wrapper">
          <div class="quiz-container">
            <div class="quiz-header">
              <h1>项目中sleep(0)是什么意思 - 交互式测验</h1>
              <p>检验你对文档内容的理解程度</p>
            </div>
            <div id="quiz-content">
                <div class="quiz-body">
                    <div class="progress-bar">
                        <div id="progress-indicator"></div>
                    </div>
                    <div id="question-container">
                      <p id="question-text"></p>
                      <ul class="options-list" id="options-list"></ul>
                    </div>
                    <div id="result-container"></div>
                    <div id="hint-container" class="hint-container"></div>
                </div>
                <div class="quiz-footer" id="quiz-footer">
                  <button id="prev-btn" class="nav-btn">上一题</button>
                  <button id="hint-btn" class="nav-btn" style="background-color: #ffc107; color: #333; box-shadow: 0 4px 12px rgba(255,193,7,0.3);">提示</button>
                  <button id="next-btn" class="nav-btn">下一题</button>
                </div>
            </div>
          </div>
      </div>

      <script>
        const quizData = [
  {
    "question": "根据文档，`sleep(0)`在多线程编程中的核心含义是什么？",
    "options": [
      "让当前线程精确地休眠0毫秒，然后立即恢复执行。",
      "强制操作系统立即执行一个优先级较低的线程。",
      "当前线程愿意让出CPU资源，进入就绪状态，以便其他优先级相同或更高的线程有机会执行。",
      "永久性地终止当前线程的执行。"
    ],
    "correctAnswerIndex": 2,
    "explanation": "`sleep(0)` 并不意味着线程真的休眠。它的核心作用是向线程调度器发出一个信号，表示当前线程愿意主动放弃CPU的执行权，从而进入就绪状态。这使得调度器可以立即选择另一个优先级相同或更高的就绪线程来执行，从而提高系统的并发性和公平性。",
    "source": "文档中「基本概念」部分",
    "hint": "文档提到 `sleep(0)` “并不会真正进入休眠状态”，而是体现了一种“愿意让出CPU资源”的行为。"
  },
  {
    "question": "在一个长时间运行的任务中插入`sleep(0)`调用，主要能带来什么好处？",
    "options": [
      "保证线程之间严格按照预定的顺序执行。",
      "提高系统的响应性和并发性能，避免单个线程长时间独占CPU。",
      "显著减少线程的内存占用。",
      "降低程序的整体功耗，因为它使CPU进入低功耗模式。"
    ],
    "correctAnswerIndex": 1,
    "explanation": "在长时间运行的任务中，线程可能会持续占用CPU，导致其他线程（如UI线程）无法得到执行，造成界面卡顿或系统响应迟钝。通过插入`sleep(0)`，该线程可以主动让出CPU，给其他线程执行的机会，从而提高系统的整体响应速度和并发处理能力。",
    "source": "文档中「使用场景」部分",
    "hint": "思考一下在长时间任务中，为什么需要让出CPU资源。文档提到，这可以“提高系统的响应性和吞吐量”。"
  },
  {
    "question": "根据文档，`sleep(0)`和`yield()`方法在线程调度上的一个主要区别是什么？",
    "options": [
      "`yield()` 是一个强制性命令，而`sleep(0)`只是一个建议。",
      "`sleep(0)` 会导致线程进入阻塞状态，而`yield()`不会。",
      "`sleep(0)` 只能在Java中使用，而`yield()`是跨语言的通用概念。",
      "`yield()` 在让出CPU时会考虑线程优先级，通常只会让给同级或更高优先级的线程。"
    ],
    "correctAnswerIndex": 3,
    "explanation": "文档明确指出，`yield()`会考虑优先级，表示当前线程愿意放弃CPU资源给“其他同优先级或更高优先级的线程”。这是`sleep(0)`与`yield()`在调度策略上的一个关键区别，`yield()`的让步行为与优先级有更强的关联。",
    "source": "文档中「与yield()的比较」部分",
    "hint": "文档在比较两者时提到了“优先级要求不同”。"
  },
  {
    "question": "相对于 `busy-waiting`（忙等待），使用`sleep(0)`的主要优势是什么？",
    "options": [
      "`busy-waiting` 能够更好地实现线程间的公平调度。",
      "`sleep(0)` 通过让出CPU来避免不必要的资源消耗，而`busy-waiting`会持续占用CPU资源。",
      "`sleep(0)` 能够比`busy-waiting`更快地响应条件的改变。",
      "`sleep(0)`会释放线程持有的所有锁，而`busy-waiting`不会。"
    ],
    "correctAnswerIndex": 1,
    "explanation": "`busy-waiting` 的核心是在一个循环中不断检查某个条件，这个过程会持续消耗CPU周期。相比之下，`sleep(0)`会让当前线程进入就绪队列，将CPU资源释放给其他线程，从而大大降低了CPU的无效消耗，是一种更高效的等待方式。",
    "source": "文档中「与busy-waiting的比较」部分",
    "hint": "考虑两种方式在等待时对CPU资源的使用情况。文档提到“CPU资源消耗不同”是它们的一个主要区别。"
  },
  {
    "question": "为什么在GUI（图形用户界面）编程中，使用`sleep(0)`可以帮助优化用户体验？",
    "options": [
      "它可以减少UI元素的绘制时间，从而直接提升渲染速度。",
      "它可以让UI线程进入休眠状态，以节省电量。",
      "它可以让耗时的后台任务线程主动让出CPU，确保UI线程能及时响应用户操作和更新界面。",
      "它可以强制UI线程以最高优先级运行，压制所有其他线程。"
    ],
    "correctAnswerIndex": 2,
    "explanation": "在GUI应用中，通常有一个专门的UI线程负责界面的渲染和用户交互。如果另一个线程执行一个长时间任务并持续占用CPU，UI线程就得不到执行机会，导致界面冻结。在耗时任务中适时调用`sleep(0)`，可以让出CPU给UI线程，从而保证界面的流畅和响应性。",
    "source": "文档中「使用场景」部分的“UI编程中的响应性优化”",
    "hint": "文档中有一个例子提到了GUI编程，思考一下UI界面为什么会“卡住”。"
  },
  {
    "question": "当一个线程调用 `sleep(0)` 时，它会转换到什么状态？",
    "options": [
      "阻塞状态（Blocked State）。",
      "终止状态（Terminated State）。",
      "就绪状态（Ready State）。",
      "真正进入休眠状态（Sleeping State）零毫秒。"
    ],
    "correctAnswerIndex": 2,
    "explanation": "文档明确指出，调用 `sleep(0)` 的实际效果是“让当前线程进入就绪状态，让其他就绪状态的线程有更多的机会被调度执行”。它并不会真正进入休眠或阻塞状态，而是回到可以被CPU调度的队列中，等待下一次被调度执行。",
    "source": "文档中「实际效果」部分",
    "hint": "文档强调，该方法“并不会真正进入休眠状态”，而是让线程有机会“被调度执行”。"
  },
  {
    "question": "从语义上看，`sleep(0)` 体现了线程的一种什么行为意愿？",
    "options": [
      "主动让步和公平调度，表示当前线程愿意与其他线程共享CPU资源。",
      "任务完成，表示当前线程已经结束其所有工作。",
      "强制独占，表示当前线程需要立即获得CPU资源。",
      "资源请求，表示当前线程正在等待某个外部资源（如I/O）。"
    ],
    "correctAnswerIndex": 0,
    "explanation": "`sleep(0)` 的语义是一种“主动让步的意愿”。它表明当前线程不是必须立即执行，而是愿意放弃CPU，让调度器有机会运行其他线程。这有助于实现更公平的CPU资源分配，避免线程饥饿等问题。",
    "source": "文档中「语义」部分",
    "hint": "文档将 `sleep(0)` 的语义概括为几个方面，其中“主动让步”和“公平调度”是核心。"
  }
];
        console.log("Quiz Data:", JSON.parse(JSON.stringify(quizData))); // 添加这行用于调试，以可展开的JSON格式输出
        
        let currentQuestionIndex = 0;
        let score = 0;
        // 存储每个问题的回答状态
        const userAnswers = new Array(quizData.length).fill(null); 

        const questionTextEl = document.getElementById('question-text');
        const optionsListEl = document.getElementById('options-list');
        const resultContainerEl = document.getElementById('result-container');
        const quizContentEl = document.getElementById('quiz-content');
        const progressIndicatorEl = document.getElementById('progress-indicator');
        const prevBtn = document.getElementById('prev-btn');
        const nextBtn = document.getElementById('next-btn');
        const hintBtn = document.getElementById('hint-btn');
        const hintContainerEl = document.getElementById('hint-container');

        function loadQuestion() {
          resultContainerEl.innerHTML = '';
          optionsListEl.innerHTML = '';
          hintContainerEl.style.display = 'none'; // 隐藏提示
          
          if (currentQuestionIndex >= quizData.length) {
            showFinalScore();
            return;
          }

          updateProgress();

          const currentQuestion = quizData[currentQuestionIndex];
          questionTextEl.textContent = `(${currentQuestionIndex + 1}/${quizData.length}) ${currentQuestion.question}`;
          
          currentQuestion.options.forEach((optionText, index) => {
            const li = document.createElement('li');
            li.className = 'option-item';
            li.textContent = optionText;
            li.dataset.index = index; // Store index in a data attribute
            // 如果这道题已经回答过，恢复状态
            if (userAnswers[currentQuestionIndex] !== null) {
                if (index === userAnswers[currentQuestionIndex]) {
                    li.classList.add('selected');
                }
            }
            optionsListEl.appendChild(li);
          });

          // 如果已经回答过，直接显示结果
          if (userAnswers[currentQuestionIndex] !== null) {
              const isCorrect = userAnswers[currentQuestionIndex] === currentQuestion.correctAnswerIndex;
              showResult(isCorrect, currentQuestion);
          }
          
          updateNavigationButtons();
          updateProgress();
        }

        function selectOption(optionIndex) {
            userAnswers[currentQuestionIndex] = optionIndex;
            const currentQuestion = quizData[currentQuestionIndex];
            const isCorrect = optionIndex === currentQuestion.correctAnswerIndex;

            // 重新计算分数
            score = userAnswers.reduce((acc, answer, index) => {
                return answer === quizData[index].correctAnswerIndex ? acc + 1 : acc;
            }, 0);

            showResult(isCorrect, currentQuestion);
            updateNavigationButtons();
        }
        
        function updateProgress() {
            const answeredQuestions = userAnswers.filter(answer => answer !== null).length;
            const progressPercentage = (answeredQuestions / quizData.length) * 100;
            progressIndicatorEl.style.width = `${progressPercentage}%`;
        }
        
        function updateNavigationButtons() {
            prevBtn.style.display = 'block';
            nextBtn.style.display = 'block';
            hintBtn.style.display = 'block'; // 显示提示按钮

            prevBtn.disabled = currentQuestionIndex === 0;
            nextBtn.disabled = false; // 最后一题时，下一题按钮不禁用，而是用于显示报告
            nextBtn.textContent = (currentQuestionIndex === quizData.length - 1) ? '查看报告' : '下一题';
            
            // 如果当前问题没有提示，则禁用提示按钮并隐藏提示内容
            if (!quizData[currentQuestionIndex].hint) {
                hintBtn.disabled = true;
                hintContainerEl.style.display = 'none';
                hintContainerEl.textContent = ''; // 清除旧的提示内容
            } else {
                hintBtn.disabled = false;
            }
        }

        function showResult(isCorrect, questionData) {
            resultContainerEl.innerHTML = ''; // 清空之前的结果
            const resultBox = document.createElement('div');
            resultBox.className = `result-box ${isCorrect ? 'correct' : 'incorrect'}`;
            
            let html = `<h3>${isCorrect ? '回答正确！' : '回答错误'}</h3>`;
            if (!isCorrect) {
                html += `<p><strong>正确答案是：</strong> ${questionData.options[questionData.correctAnswerIndex]}</p>`;
            }
            html += `<div class="explanation-text">${questionData.explanation}</div>`;
            html += `<div class="source-text">来源: ${questionData.source}</div>`;
            
            resultBox.innerHTML = html;
            resultContainerEl.appendChild(resultBox);

            // 禁用所有选项的点击事件，并高亮正确/错误答案
            Array.from(optionsListEl.children).forEach((child, index) => {
                child.style.pointerEvents = 'none';
                // 高亮正确答案
                if (index === questionData.correctAnswerIndex) {
                    child.classList.add('correct'); // 需要添加CSS样式
                    child.style.backgroundColor = '#d4edda';
                    child.style.borderColor = '#c3e6cb';
                }
                // 如果选错了，高亮错误选项
                if (!isCorrect && index === userAnswers[currentQuestionIndex]) {
                    child.classList.add('incorrect'); // 需要添加CSS样式
                    child.style.backgroundColor = '#f8d7da';
                    child.style.borderColor = '#f5c6cb';
                }
            });
        }

        function goToNextQuestion() {
            if (currentQuestionIndex < quizData.length - 1) {
                currentQuestionIndex++;
                loadQuestion();
            } else {
                showFinalScore();
            }
        }

        function goToPreviousQuestion() {
            if (currentQuestionIndex > 0) {
                currentQuestionIndex--;
                loadQuestion();
            }
        }
        
        function showHint() {
            const currentQuestion = quizData[currentQuestionIndex];
            if (currentQuestion.hint) {
                hintContainerEl.textContent = currentQuestion.hint;
                hintContainerEl.style.display = 'block';
            } else {
                hintContainerEl.style.display = 'none';
            }
        }

        function showFinalScore() {
            document.querySelector('.quiz-body').style.display = 'none';
            document.getElementById('quiz-footer').style.display = 'none';

            const correctCount = score;
            const totalQuestions = quizData.length;
            const answeredCount = userAnswers.filter(a => a !== null).length;
            const wrongCount = answeredCount - correctCount;
            const skippedCount = totalQuestions - answeredCount;
            const accuracy = totalQuestions > 0 ? Math.round((correctCount / totalQuestions) * 100) : 0;
            const errorRate = totalQuestions > 0 ? Math.round((wrongCount / totalQuestions) * 100) : 0;

            const finalScoreHtml =
                '<div class="final-score-container">' +
                '<h2>答题报告</h2>' +
                '<div class="score-summary">' +
                '<div class="score-card">' +
                '<h3>得分</h3>' +
                '<p>' + correctCount + ' / ' + totalQuestions + '</p>' +
                '</div>' +
                '<div class="score-card">' +
                '<h3>正确率</h3>' +
                '<p>' + accuracy + '%</p>' +
                '</div>' +
                '<div class="score-card">' +
                '<h3>错误率</h3>' +
                '<p>' + errorRate + '%</p>' +
                '</div>' +
                '<div class="score-card score-details">' +
                '<table>' +
                '<tr><td>正确</td><td>' + correctCount + '</td></tr>' +
                '<tr><td>错误</td><td>' + wrongCount + '</td></tr>' +
                '<tr><td>未答</td><td>' + skippedCount + '</td></tr>' +
                '</table>' +
                '</div>' +
                '</div>' +
                '<div class="report-actions">' +
                '<button id="review-btn">回顾测验</button>' +
                '<button class="primary" onclick="location.reload()">再试一次</button>' +
                '</div>' +
                '</div>';

            let reportEl = document.querySelector('.final-score-container');
            if (reportEl) {
                reportEl.remove();
            }
            quizContentEl.insertAdjacentHTML('beforeend', finalScoreHtml);
            document.getElementById('review-btn').addEventListener('click', reviewQuiz);
        }

        function reviewQuiz() {
            const reportEl = document.querySelector('.final-score-container');
            if (reportEl) {
                reportEl.remove();
            }

            document.querySelector('.quiz-body').style.display = 'block';
            document.getElementById('quiz-footer').style.display = 'flex';
            
            currentQuestionIndex = 0;
            loadQuestion();
            updateNavigationButtons(); // Ensure nav buttons are correctly displayed
        }

        // Event Delegation for options
        optionsListEl.addEventListener('click', (event) => {
            if (event.target && event.target.matches('li.option-item')) {
                // Check if the question has already been answered
                if (userAnswers[currentQuestionIndex] === null) {
                    const selectedIndex = parseInt(event.target.dataset.index, 10);
                    selectOption(selectedIndex);
                }
            }
        });

        prevBtn.addEventListener('click', goToPreviousQuestion);
        nextBtn.addEventListener('click', goToNextQuestion);
        hintBtn.addEventListener('click', showHint);
        
        // 初始加载
        loadQuestion();
      </script>
    </body>
    </html>
  